USE OF NUCLEAR MAGNETIC RESONANCE AND NEW CORE ANALYSIS TECHNOLOGY FOR DETERMINATION OF GAS SATURATION IN PRETTY HILL SANDSTONE RESERVOIRS, ONSHORE OTWAY BASIN

1999 ◽  
Vol 39 (1) ◽  
pp. 437
Author(s):  
P.J. Boult ◽  
R. Ramamoortby ◽  
P.N. Theologou ◽  
R.D. East ◽  
A.M. Drake ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Saturation ◽  
Pressure Curve ◽  
Core Analysis ◽  
Gas Saturation ◽  
Combined Application ◽  
Nuclear Magnetic Resonance Response ◽  
Log Interpretation ◽  
Nuclear Magnetic

The failure of conventional log interpretation of low resistivity gas-bearing reservoirs in the Lower Cretaceous Pretty Hill Sandstone, onshore Otway Basin, has led to the use of the saturation versus height, Leverett J function as a basis for predicting hydrocarbon saturation.The recent application of a new method of proprietary core analysis (corEVAL™*) in the 1998 gas discovery well Redman–1, allowed the derivation of a more realistic Leverett J function to water saturation transform for the Pretty Hill Sandstone. Furthermore, this transform could be applied beyond the cored interval to the remaining reservoir section by calibrating the core with its nuclear magnetic resonance response. An algorithm, which converts Schlumberger's combinable magnetic resonance (CMR*) cumulative T2 distributions into a pseudo- capillary pressure curve, has been derived enabling the calculation of gas saturation directly from this log. The CMR derived permeability log also assisted in facies differentiation of the reservoir section and in the selection of wireline pressure and formation fluid sampling points.The combined application of nuclear magnetic resonance technology and proprietary core analysis, independently validated by formation sample and test data, resulted in a 30% increase over previous methods, in average gas saturation in the reservoir being calculated. This has lead to a predicted increase in estimated gas in place at the Redman Field

Case study of quantification of oil viscosity and saturation in complex reservoirs using advanced nuclear magnetic resonance log interpretation techniques

2011 ◽  
Vol 51 (2) ◽  
pp. 725
Author(s):  
Adrian Manescu ◽  
Keith Boyle
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Clay Content ◽  
Hydrocarbon Exploration ◽  
Fluid Viscosity ◽  
Oil Viscosity ◽  
Porosity Distribution ◽  
Nmr Data ◽  
Log Interpretation ◽  
Nuclear Magnetic

In the hydrocarbon exploration process, after a prospect has been identified and an exploration well has been drilled, a critical piece of information is the oil type. Earlier wireline or while-drilling well-logging technologies provided rock properties and saturation information, but relied on expensive sampling and testing to determine oil properties. This weakness was overcome through the introduction of nuclear magnetic resonance (NMR) logs that can provide formation properties—lithology-independent porosity, porosity distribution, permeability, etcetera—and information about the reservoir fluid viscosity. NMR data were recently acquired in complex, high-clay content, low-salinity oil reservoirs. Traditional petrophysical interpretations throughout these reservoirs were confronted with a complex lithology—comprising feldspathic litharenites and volcanic lithic components—high clay content and low formation water salinity, of 3-4 Kppm NaCl eq. This extended abstract shows how acquisition and interpretation of NMR data not only provided porosity and porosity distribution, but also identified oil viscosity across the logged intervals. Advanced NMR log interpretation techniques (2D-NMR maps of diffusion (D) versus T2, int) were used to identify oil NMR signal. This technique produced a continuous profile of diffusion and intrinsic T2 distribution maps. Once the oil NMR signal was identified, an estimation of the oil viscosity was also possible because D and T2, int are related with viscosity. Several available correlations have been used and results were comparable with production data.

Static Measurements Enhance Saturation and Permeability Interpretation

2021 ◽  
Vol 73 (08) ◽  
pp. 46-47
Author(s):  
Chris Carpenter
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Saturation ◽  
Data Gathering ◽  
Abu Dhabi ◽  
Rock Properties ◽  
Well Test ◽  
Reservoir Properties ◽  
Nuclear Magnetic

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202683, “Marrying the Static and Dynamic Worlds: Enhancing Saturation and Permeability Interpretation Using a Combination of Multifrequency Dielectric, Nuclear Magnetic Resonance, and Wireline Formation Testers,” by Hassan Mostafa, Ghassan Al-Jefri, SPE, and Tania Felix Menchaca, SPE, ADNOC, et al., prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed. Accurate water saturation evaluation and permeability profiling are crucial factors in determining volumetrics and productivity of multiple, stacked carbonate reservoirs offshore Abu Dhabi and derisking reservoir management. The case study presented in the complete paper illustrates how the integration of static measurements, such as dielectric dispersion and nuclear magnetic resonance (NMR) with dynamic measurements improves understanding of reservoir properties and supports more-accurate reservoir evaluation. Sampling and downhole fluid analysis (DFA) performed by wireline formation tester (WFT) identifies the fluid and rock properties in various flow units. Field Background and Challenges Optimal field development requires accurate estimations of water saturation and permeability. In this greenfield, the hydrocarbon is generally oil (medium to light) with very low asphaltene content. Overall, the reservoir quality is controlled by a combination of depositional environment, sequence stratigraphy, and diagenesis. Some reservoirs have good porosity, but reconciliation of log-based water saturation results with well-test results has been an issue. The objective in this case study was to drill a pilot hole for data gathering in a poorly characterized field location. Phase I included drilling a hole with a 55° deviation to cover all reservoirs for data gathering only, with the openhole reservoir section then being plugged and abandoned. Phase II of the plan was to sidetrack and complete the well as dual water-injector boreholes. In the reservoir section of the pilot borehole, a variety of logs was acquired for evaluation, including both logging-while-drilling and wireline measurements. While drilling, triple- combination data were acquired, consisting of gamma ray, resistivity, and nuclear logs (density neutron) along with resistivity images. The wireline-logging program was carried out in two stages to avoid differential sticking. In the first stage, the WFT was used to acquire 10 pressure points, seven points in the first reservoir and three points in the second. Two DFA stations were also recorded in Zone 1 to confirm whether the oil/water contact was deeper than expected. Logging was conducted using a high-tension wireline cable, which facilitates quicker accessibility to the openhole sections. In the second stage, multiple wireline runs were performed for the formation evaluation of the complete section, followed by the WFT pressure and fluid-sampling run on the drillpipe conveyance. Another critical challenge was to obtain accurate water saturations in the heterogeneous, minor, thin reservoirs, which are bounded by dense layers above and below and cause shoulder-bed effects. The third challenge in this well was to obtain an accurate, continuous, and representative permeability profile for the multiple reservoirs. WFT mini-drillstem test (DST) stations along with NMR logs were used to address this important requirement.

The effect of tetra-n-butylammonium salts on the nuclear magnetic resonance of nitrobenzene

1968 ◽  
Vol 46 (1) ◽  
pp. 74-74 ◽  
Author(s):  
J. B. Hyne ◽  
A. R. Fabris
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Ring ◽  
Specific Interaction ◽  
Ion Pair ◽  
Carbon Tetra ◽  
Resonance Response ◽  
Nuclear Magnetic Resonance Response ◽  
Nuclear Magnetic

Tetra-n-butylammonium salts effect the nuclear magnetic resonance response of the para and meta protons of nitrobenzene to a greater extent than that of the ortho protons in solutions in carbon tetra chloride. It is suggested that this effect may be due to a specific interaction between the salt, in ion-pair form, and the aromatic ring of nitrobenzene.

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